Carpet cutter



E. F. PRATER CARPET CUTTER Aug. 6, 1968 2 Sheets-Sheet 1 Filed April 28,1967 FIG. 1.

m RT 6 TR P F N5 L m E N W 7 H w V 5 Haze/s, K150 P035251. L &/(/?NUnited States Patent 3,395,453 CARPET CUTTER Earle F. Prater, LongBeach, Calif., assignor to Roberts Consolidated Industries, Inc., Cityof Industry, Calif., a corporation of California Filed Apr. 28, 1967,Ser. No. 634,601 5 Claims. (Cl. 30-293) ABSTRACT OF THE DISCLOSURE Atool for trimming carpet, including a base plate for sliding over thetop of the carpet along an edge to be trimmed, and a blade holderpivotally connected to the base plate and supporting a pair ofoppositely oriented, downwardly inclined carpet-cutting blades.

Disclosure The present invention relates to carpet trimming and cuttingdevices and, more particularly, to an improved device for trimming theedge of a cushion back carpet when laid on a floor.

The term cushion back carpeting is applied generally to carpeting havinga sponge or foam rubber backing bonded directly to the nap of thecarpeting. Such cushion back carpeting is installed by coating the floorwith a suitable adhesive material and then laying the carpeting flatover the adhesive on the floor. As the adhesive dries, it firmlyconnects the sponge or foam rubber backing to the floor to securely holdthe carpet in place.

Where cushion back carpeting is to extend wall to Wall, it is extremelyimportant that the edges thereof fit snugly but not too tightly againstthe walls at and immediately above the floor. In particular, if thecarpeting is too long or wide and the excess is forced against thewalls, transverse forces are exerted on the foam or sponge backing whicheventually cause the backing to separate from the floor at a pointspaced from the wall and a wrinkle to be produced in the carpeting. Ifthe carpeting is too short or if its edges do not follow the contour ofthe walls, gaps are produced between the walls and the edges of thecarpeting which are unsightly and permit dirt and other debris tocollect along the junctions of the floor and walls and to work their wayunder the carpeting.

Since carpeting does not come precut to the exact dimensions of a roomand since walls invariably include minor surface irregularities, toproduce the desired snug fit between the edges of a cushion back carpetand the walls of a room, it is necessary during installation of thecarpeting to cut and trim the edges to follow the exact contour of thewalls adjacent the floor. Carpet cutting or trimming tools are employedfor this purpose and, generally speaking, comprise a flat base plate anda blade holder assembly. The base plate is designed to slide over andpress downwardly on the top of the carpeting and to carry the bladeholder assembly. The blade holder assembly, in turn, carries one or morehorizontal blades and is designed to cut upwardly turned carpeting alonga plane parallel to the floor. In this regard, and during carpetinstallation, edge portions of the carpeting are folded upwardly alongthe walls at the floor edges to follow the general contour of the walls.The cutting tool is then moved tightly over the carpet and against theupwardly turned edge portions to follow the contour of the wall. As thetool is moved, the carpet is cut by the horizontal blade along the planeparallel to the floor.

For conventional carpeting, the foregoing operation produces asubstantially squared carpet edge which will butt against the adjacentwall. Such is not the case however, for cushion back carpeting. Inparticular, when 3,395,453 Patented Aug. 6, 1968 'ice cushion backcarpeting is folded at the edge of a floor to follow the contour of awall prior to cutting, the nap and the upper surface of the backing arecompressed while the bottom of the backing is stretched. After cuttingwith a conventional horizontal blade assembly, the nap and upper surfaceof the backing expand laterally while the bottom portion of the backingcontracts, producing an inwardly inclined edge which will not buttsquarely and snugly against the adjacent wall. Accordingly, dirt andother debris is free to work its way under the carpeting and to causethe bond between the adhesive and the backing to eventually break down.This, in turn, permits undesired movement of the carpet, furtherdestroying the connection of the carpet to the floor and with it theunder surface of the cushion backing. Alternatively, the carpeting maybe out long in an attempt to compensate for the inclined nature of theresulting carpet edge. This, however, results in a condition where thenap and major portion of the backing are transversely compressed at thewall and eventually produces wrinkles in the carpeting near the wall.

In view of the problems associated with the trimming of cushion backcarpeting with conventional tools, it is an object of the presentinvention to provide an improved device for trimming the edge of cushionback carpeting which will produce squared carpet edges adapted to fitsnugly against adjacent walls.

Another object of the present invention is to provide an improved carpettrimming device which is easily adjustable to permit its cutting bladesto cut at different heights above the floor and at different angles toinsure a squared carpet edge and snug fit against an adjacent wall forcushion back carpeting of different thickness and backing types.

A further object of the present invention is to provide a carpet trimmerof the foregoing character which is adapted to handle different typeblades and is adjustable to permit control of the amount of projectionof the blades such that the trimmer may efficiently trim carpets ofdifferent thickness.

Still another object of the present invention is to pro vide an improvedcushion back carpet cutting device which will follow the surface of anadjacent wall to insure that the resulting carpet edge closely followsthe contour of the wall.

A still further object of the present invention is to provide animproved cushion back carpet trimmer which is adapted to trim campet asit is moved in either a forward or a rearward direction.

Another and more specific object of the present invention is to providean improved carpet trimmer including a base plate for riding over thetop surface of a cushion back carpet adjacent an edge thereof and havinga blade holder pivotally connected thereto for vertical swingingmovement such that the blade canried thereby may be adjusted verticallyto cut the carpet at dilferent heights above the base plate and at anangle which will insure a squared carpet edge for fitting snugly againstan adjacent wall.

The foregoing as well as other objects and advantages of the presentinvention may be more clearly understood by reference to the followingdetailed description when considered with the drawings which, by way ofexample only, illustrate a form of carpet trimmer embodying the featuresof the present invention.

In the drawings:

FIG. 1 is a side view of the carpet trimmer, partially in section,illustrating the manner in which the trimmer severs the upwardly turnededge of a cushion 'back carpet along a wall to produce a squared carpetedge which will butt snugly against the wall;

FIG. 2 is a top view of the carpet trimmer taken along the line 2-2 inFIG. 1;

FIG. 3 is a fragmentary sectional view taken along the line 3-3 in FIG.2; and

FIG. 4 is a fragmentary sectional view taken along the line 44 in FIG.2.

In the drawings, the carpet-cutting or trimming tool is representedgenerally by the numeral 10, and is adapted to slide over the top of acushion-back carpet 12 and tightly against an upturned edge portion 14hearing against a wall 16. The tool is designed to sever the edgeportion 14 on a downwardly inclined angle adjacent the carpet fold. Bycutting on such a downward angle, the tool 10 compensates for thepreviously referred to contraction and expansion of a backing 18 and nap20 of the cushion back carpet 12 and produces a substantially squaredcarpet edge for butting snugly against the wall 16. The tool 10 is alsoadjustable to cut cushion back carpeting of different backing types andthicknesses and in each instance to produce a substantially squaredcarpet edge.

To accomplish the foregoing, the tool 10 includes a blade carryingattachment 20 which may be attached to different forms of handlemechanisms, such as 22, and which therefore may be sold as a separateitem. Generally speaking, the blade carrying attachment 20 comprises abase 24, a blade holder 26, and an adjustment device 28.

The base 24 includes a generally flat rear portion 30 and a generallyfiat front portion 32 slightly below the level of the rear portion andconnected thereto by an inclined portion 34. The front portion 32includes upturned ends 36 and is designed to slide over and in contactwith the top surface of the carpet 12, with an upstanding guide 38bearing tightly against the carpet edge portion 14 to follow the contourof the wall 16 adjacent the floor 39.

As illustrated most clearly in FIG. 2, the guide 38 preferably is avertical flange extending upwardly from a midportion of the base 24 withrearwardly converging right front and left rear portions. Thusconstructed, as the guide 38 is moved firmly along the carpet edgeportion 14, it bears tightly against the edge portion and hence the wall16 at two spaced points which, as will be described in detailhereinafter, are forward of the blade severing the carpet. This insuresthat the tool 10 closely follows the contour and any irregularities inthe surface of the wall 16 adjacent the floor 39 and that the resultingcarpet edge will likewise closely follow the contour of the wallsurface.

The rear portion 30 of the base 24 is designed for connection to thehandle mechanism 22 which, by way of example only, is illustrated asbeing of the form described in US. Letters Patent No. 2,772,474, issuedDec. 4, 1956. Although details of the handle mechanism 22 may best beunderstood by reference to the patent, for purposes of thisspecification, the rear portion 32 is disposable between any twoadjacent spacer plates 40 of the handle mechanism and is provided with apair of spaced stud receiving slots 42 which engage studs 44 extendingupwardly from a base plate 46 of the handle mechanism. Downwardly struckattachment locking tabs 48 (FIGS. 1 and 2) provided on the under surfaceof the rear portion 32 extend over the rear edge of the supportingspacer plate 41] to resist outward movement of the base 24 and hence theattachment 20 upon connection to the handle mechanism 22. In thisrespect, the spacer plates 40 are locked firmly against the top andbottom of the rear portion 30 by turning knurled nuts 50 on the threadedstuds 44 tightly against the top of the spacer plates.

In addition to the spacer plates 40 and base plates 46, the [handlemechanism 22 includes an upwardly extending handle 52, adapted to begrasped by a carpet installer during operation of the tool 10 to severthe edge 4 portion 14 of the carpet 12. The handle 52 may be connectedto the base plate 46 by any suitable means such as screws (not shown)extending vertically through the base plate into opposite extremities ofthe handle.

Not only does the rear portion 30 of the base 24 provide means forconnecting the handle mechanism 22- to the base, but it also includesupwardly extending ears 51 at the sides thereof for receiving pivots 54,to pivotally connect the blade holder 26 to the base for verticalswinging movement relative thereto. In this regard, the illustrated formof the blade holder 26 includes vertically extending flanges 56 alongthe sides of the ears 51 and the pivots 54 extend horizontally throughthe flanges and the ears to pivotally connect the blade holder to thebase 24.

A support plate 58 is connected between the flanges 56 and is downwardlyand outwardly inclined toward the front of the base. The support plate58 is designed to canry a pair of carpet cutting blades 60 and 61 and tosupport the blades at an acute angle relative to and over the front ofthe base 24. The support plate 58 is also vertically adjustable tocontrol the height of the blades 60 and 61 above the base 24 and theacute angle at which the cutting one of the blades severs the carpet 12to insure that the resulting carpet edge is a squared edge which willbutt snugly against the wall 16.

To provide the desired vertical adjustability of the support plate 58and hence of the blades 60 and 61, the blade carrying attachment 20includes the adjustment device 28 for selectively setting and lockingthe support plate in various vertical positions above the base 24 withthe blade holder 26 swinging vertically on the pivots 54. By way ofillustration only, the adjustment device 28 is represented as comprisinga threaded stud 64, a coil spring 66 and a wingnut 68 (see FIG. 3). Thestud 64 is fixed to and extends vertically from the middle of the frontportion 32 of the base 24 and through an opening 70 in the support plate58. The coil spring 66 is around the threaded stud 64 on top of the base24 and bears upwardly on the under surface of an upwardly struckshoulder 72 formed in the support plate and including the opening 70.The wingnut 68 is threadedly engaged on the upper end of the threadedstud 64 and bears on the top surface of the shoulder 72, around theopening 70.

Thus arranged, the spring 66 normally urges the blade holder 26 upwardlyaway from the base 24 tending to swing the blade holder in a clockwisedirection on the pivots 54 as viewed in FIG. 1. Such swinging of theblade holder 25, however, is resisted by the wingnut 66 on the stud 64and rotation of the wingnut in one direction, rotates the blade holderclockwise on the pivots 54 while rotation thereof in the reversedirection permits counterclockwise rotation of the blade holder on itspivots by the spring 66. Such vertical adjustment of the blade holder 26by swinging on its pivots 54 controls the height and slightly varies theangle of the blades 60 and 61 relative to the base and hence the angleat which the carpet edge portion 14 is severed. By proper adjustment ofthe wingnut 68, the cutting angle may be set to fully compensate for thepreviously referred to contraction and expansion of the cushion backcarpeting 12, which normally occurs after a severance of the edgeportion 14 therefrom, thereby producing a squared carpet edge.

With regard to such contraction and expansion and the compensationtherefor and as illustrated most clearly in FIG. 1, when the carpeting12 is folded upwardly against the wall 16, the nap 20 and upper surfaceof the backing 18 are compressed along and adjacent to the fold of thecarpet while the lower portion of the backing is extended. This meansthat when the carpet edge portion 14 is severed, the nap 20 and uppersurface of the backing 18 will expand laterally and the lower portion ofthe backing will contract. Therefore, to produce the desired squaredcarpet edge, the cutting one of the blades 60 and 61 should sever thecarpet along an acute angle relative to the horizontal base 24 and floor39. In particular, by cutting the edge portion 14 at the proper angle,the nap 20 and backing 18 will expand and contract to form asubstantially squared edge which will butt snugly against the wall 16.

The foregoing vertical adjustment feature of the blade holder 26 alsoinsures a resulting squared carpet edge upon severance of the edgeportions of carpets of different types of cushion backing and differenttypes of nap. In particular, irrespective of the expansion andcontraction characteristics of the nap and backing, the blade holder 26may be vertically adjusted to cause the blades to cut the edge portionof the carpet at an angle which will produce a substantially squaredcarpet edge. Furthermore, by vertical adjustment of the blade holder 26,such various types of cushion back carpeting may be cut at differentheights above the floor to insure that the resulting carpet edge willbutt against the adjacent wall.

It is also an important feature of the attachment 20 that it willefiiciently trim edge portions of cushion back carpeting of variousthicknesses. This is accomplished by the inclusion of a hand adjustableblade support device 74. The blade support device 74 also allows theblade holder 26 to support different types of carpet cutting blades ofvarious shapes such as a slotted blade (the form illustrated) and theso-called Universal trimmer blade.

Generally speaking, the blade support device 74 sup ports the blades 60and 61 on top of the support plate 58 and permits manual adjustment ofthe projection of the blades beyond the front of the base 24 inaccordance with the thickness of the carpeting being severed by the tool10. In this regard, it is of course desired that the cutting one of theblades 60 and 61 extend completely through the carpeting withoutengaging and hence marring the surface of the wall 16 during severanceof the carpet edge portion 14. The blade support device 74 also isdesigned to angularly orient the cutting edges of the blades 60 and 61with respect to the angular plane of the blades so that during cuttingoperation, the blade cutting edge exerts a shearing action on the carpetthereby reducing the chances of tearing or otherwise marring the carpet.

To accomplish the foregoing, the blade support device 74 comprisesforwardly diverging channels 76 and 78, one on each side of the shoulder72 on the support plate 58, a cover plate 80 and a pair of handadjustable set screws 82 and 84.

As illustrated most clearly in FIGS. 2 and 4, the

channels 76 and 78 are formed by two pairs of upwardly struck parallelridges 86 and 87 extending upwardly and rearwardly along the uppersurface of the support plate 58. The blades 60 and 61 are adapted toslide along the channels 76 and 78 up and down the face of the supportplate 58.

The cover plate 80 is generally V-shaped and dimensioned to fit over thetop of the support plate 58 around the shoulder 72 with left and rightportions extending over the channels 76 and 78, respectively. Elongatedslots 88 are included in the cover plate 80 over central portions of thechannels 76 and 78 to permit hand contact with the blades 60 and 61whereby the blades may be moved longitudinally within the channels whenthe cover plate is not clamped firmly to the support plate.

In this regard, the cover plate 80 includes a pair of cars 90 extendingfrom front edge portions thereof on opposite sides of the shoulder 72.The ears 90 extend into slots 92 in upwardly extending flanges 94 fromthe support plate 5'8. The cover plate 80 is adapted to bear on topsurfaces of the support plate 58 adjacent the ridges 86 (and on theblades 60 and 61 when in the channels) with the ears bearing on the topsof the slots 92. From the channels 76 and 78, the cover plate 80 iseffectively cantilevered over the top surface of the support plate 58(see FIG. 4) to receive the set screws 82 and 84 at upper left and rightportions adjacent the ends of the support plate the set screws passingthrough openings 96 in the cover plate and screwing into threaded holes98 in the support plate. When the set screws are not tightened down onthe cover plate 80, the blades 60 and 61 may be slid by hand up and downthe inclined channels 76 and 78. However, upon a tightening of the saidscrews, the cover plate 80 is forced tightly onto the top of the blades60 and 61 with the ears hearing tightly on the tops of the slots 92 inthe flanges 94. The blades 60 are thus clamped in position within thechannels.

When the tool 10 is not in use, the blades 60 and 61 may be completelyrecessed in the channels 76 and 78 and under the cover plate 80 with agenerally triangular ridge 100 immediately to the rear of the shoulder72 acting as a stop preventing the blades from riding upwardly out ofthe channels. When it is desired to utilize the tool 10, the set screws82 and 84 are loosened to unlock the blades from the blade holder 26.One or the other of the blades may then be moved by hand to project fromits associated channel beyond the front edge of the base 24 an amountcontrolled by the thickness of the cushion back carpeting to be severedby the tool. If the tool is to sever the edge portion 14 of the carpet12 by rearward pushing movement, when viewed in FIG. 1, the blade 60 isextended while the blade 61 is maintained recessed within its channel78. The converse is true if the carpet edge portion is to be severed byforward pulling movement of the tool. The set screws are then againtightened to lock the blades in their respective positions therebyreadying the tool for use in severing the carpet edge portion 14.

By way of summary and review, when a carpet installer desires to trimthe edge portion 14 of the cushion back carpeting 12 and to create asquared carpet edge which will abut firmly against the wall 16, he firstloosens the set screws 82 and 84 and selectively adjusts the blade 60 tothe desired projection. That is, he extends the blade 60 such that itsprojection beyond the front of the base 24 and guide 38 is slightlygreater than the thickness of the carpeting. The installer thenretightens the set screws to lock the blades in place, the blade 61remaining recessed in its channel 78 under the cover plate 80.

Next, by turning the wingnut 68, the installer adjusts the height of theblade 60 above the base 24 such that the blade will sever the carpetedge portion 14 at an acute angle and such that the new edge portion ofthe carpeting 12 will expand and contract and form a substantiallysquared carpet edge for butting snugly against the wall 16.

Having thus pre-adjusted the tool 10, the installer grasps the handle 52and presses the tool downwardly on the top surface of the carpet 12 andthe guide 38 tightly against the edge portion 14. He then pushes thetool rearward, when viewed in FIG. 1, along the edge portion 14 with theguide making a two-point contact with the carpeting forward of cuttingblade 60. This insures that the tool closely follows the contour and anyirregularities in the wall 16 and that the resulting edge will closelyfollow the surface of the wall adjacent the floor 39.

As the tool 10 is pushed rearward, the downwardly inclined angularlyoriented cutting edge of the blade 60 shears the cushion back carpetingleaving a smooth, clean carpet edge for abutting against the wall 16.The cutting operation is repeated for each edge of the carpeting 12 tocomplete the installation of the wall-to-wall carpeting.

In view of the foregoing, it is appreciated that the present inventionprovides an improved device for trimming the edge of cushion backcarpeting which produces squared carpet edges adapted to fit snuglyagainst adjacent walls and which is adjustable to produce such squarededges for cushion back carpeting of different thickness and differentbacking types.

While a particular form of carpet trimmer has been described in somedetail herein, changes and modifications may be made in the illustratedform without departing from the spirit of the invention. It is thereforeintended that the present invention be limited in scope only by theterms of the following claims.

I claim: 1. In a cutting tool, the combination of: base means havingfront and rear portions; blade holder means having front and rearportions, including means for supporting a cutting blade at an angle tothe lower surface of said base means and projecting over said frontportion of said base means;

pivot means for pivotally supporting said rear portion of said baseholder means on said rear portion of said base means for rotationalmovement of said blade holder means with respect to said base means; and

adjustment means between said base means and said blade holder means foradjusting the rotational position of said blade holder means relative tosaid base means including spring means between said base means and saidblade holder means for continuously urging said blade holder means awayfrom said base means and hand turnable means connected to said basemeans and bearing on said blade holder means for adjusting the verticalheight of said blade holder means relative to said base means by aturning thereof.

2. The combination of claim 1 wherein said combination further comprisesa threaded stud extending vertically from said base means and through anopening in said blade holder means and said hand turnable means includesa nut on said stud and bearing on said blade holder means to adjust thevertical height of said blade holder means on said stud by a turningthereof.

3. The combination of claim 1 wherein said front portion of blade holdermeans is downwardly and forwardly inclined and wherein said combinationfurther includes support means for connecting a cutting blade to saidfront portion of said blade holder means to extend at an acute anglerelative to said base means.

4. The combination of claim 3 wherein said support means comprises:

a channel on said inclined front portion of said blade holder means forslidably receiving said blade; a cover plate extending over saidchannel; and hand operable means for pressing said cover plate onto saidblade to lock said blade in said channel. 5. The combination of claim 3wherein: said tool includes first and second blades; and said supportmeans connects said first and second blades to said inclined frontportion of said blade holder means and at an acute angle relative tosaid base means and includes first and second forwardly extending andoutwardly diverging channels on said front portion of said blade holdermeans for slidably receiving said first and second blades respectively,

a cover plate cantilevered from said front portion of said blade holdermeans over said channels and said blades,

and screw means through said cover plate and into upper rear portions ofsaid front portion adjacent ends thereof for pressing said cover plateonto said blades in said channels to releasably lock said blades to saidblade holder means.

References Cited UNITED STATES PATENTS 2,065,761 12/1936 Smith 30-2932,037,133 7/1937 Fulton 30-239 2,772,474 12/1956 Hill et al. 20-2932,306,233 9/1957 Brennan 30-294 3,337,955 3/1967 Poletajev 30-294 JAMESL. JONES, 111., Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION August 6, 1968Patent No. 3,395,453

Earle F. Prater It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected asshown below:

Column 7, line 15, "base" should read blade Signed and sealed this 3rdday of February 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

